Field of the Invention
The disclosed technology generally relates to semiconductor devices, and in relates particularly to devices comprising Schottky diodes having a junction between a metal and a group III metal nitride semiconductor.
Description of the Related Technology
Different types of diodes can be integrated in integrated circuit devices. Diodes are often categorized based on their types of junctions. For example, a diode can include a junction formed by a p-type semiconductor and an n-type semiconductor, in which case the diode is referred to as a PN diode. On the other hand, a diode can include a junction formed by a metal and an n-type or a p-type semiconductor, in which case the diode is referred to as a Schottky diode. Schottky diodes are widely used in rectifying circuits because of their relatively low forward voltage drop and fast switching characteristics. In particular, Schottky diodes produced on AlGaN/GaN heterostructures benefit from the high breakdown voltage of the GaN and the high mobility and high electron density of the 2DEG-layer (2-dimensional electron gas) appearing between the GaN and the AlGaN layer as a result of the difference of piezoelectric and spontaneous polarization. Such Schottky diodes, however, sometimes can have high leakage current when the diode is reverse-biased, which can result in an increased power loss for an electronic device. US Patent Application 2011/0133251 discloses a GaN/AlGaN based Schottky diode structure comprising a stack of a GaN layer and an AlGaN layer, with a metal anode on top of the AlGaN layer forming a Schottky contact therewith, and a metal cathode on the AlGaN layer forming an ohmic contact therewith. A field dielectric layer separates the anode and cathode electrically.